弱激光对神经元钾离子通道特性影响的实验研究

Research on characteristics of neuron potassium channel under low level laser irradiation

利用波长为670nm、功率为5mW的半导体激光器照射急性分离的大鼠海马CA3区锥体神经元,应用全细胞膜片钳技术研究其瞬时外向钾离子通道特性.实验发现:弱激光对瞬时外向钾电流具有抑制作用,并且该抑制作用呈现电压依赖性和可逆性.激光作用可显著影响通道稳态激活和失活过程,激光照射组和对照组比较,电流稳态激活曲线向去极化方向移动,半数激活电压升高,曲线斜率因子改变;而失活曲线向超极化方向移动,半数失活电压降低,曲线斜率因子不变.结果表明,弱激光作用海马神经细胞可以改变其瞬时外向钾离子通道特性,从而影响动作电位的形成和发放,调节神经元生理功能,有利于受损神经元的恢复和再生.

Acutely isolated rat hippocampal CA3 pyramidal neurons were irradiated with a semiconductor laser of wavelength 670 nm and power 5 mW. The properties of transient outward potassium （K^＋ ） channel were investigated using the whole-cell patch clamp technique. The experiment revealed that low level laser reduced the amplitudes of IA in a voltage-dependent and reversible manner. The steady-state activation and inactivation processes of IA were significantly affected by laser irradiation. And the steady-state activation curve shifted towards positive potential direction, altering the slope factor of curve and increasing the haftactivation voltage. However, the steady-state inactivation curve shifted towards negative potential direction, reducing the halfinactivation voltage without changing the slope factor. The results show that low level laser irradiation could change the characteristics of transient outward K^＋ channel. Accordingly, the firing of action potential and the physiological function of neurons were adjusted as a result of low level laser irradiation, which might contribute to the recovery and regeneration of injured neurons.